Method of controlling equipment in a heating, ventilation and air conditioning network

ABSTRACT

The disclosure provides an HVAC data processing and communication network and a method of manufacturing the same. In an embodiment, the network includes a sensor and a local controller. The sensor is configured to detect a fault condition associated with operation of a demand unit. The local controller, associated with the demand unit, is configured to receive sensor data from the sensor and to communicate the sensor data over the network. A network controller is configured to receive the sensor data via the communication network and to generate an alert in the event that the sensor data indicates the fault condition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 61/167,135, filed by Grohman, et al., on Apr. 6, 2009, entitled “Comprehensive HVAC Control System”, and is a continuation-in-part application of application Ser. No. 12/258,659, filed by Grohman on Oct. 27, 2008, entitled “Apparatus and Method for Controlling an Environmental Conditioning Unit,” both of which are commonly assigned with this application and incorporated herein by reference. This application is also related to the following U.S. patent applications, which are filed on even date herewith, commonly assigned with this application and incorporated herein by reference:

Ser. No. Inventors Title [Attorney Grohman, et “Alarm and Diagnostics System and Method Docket al. for a Distributed-Architecture Heating, No. Ventilation and Air Conditioning 080161] Network” [Attorney Wallaert, “Flush Wall Mount Controller and In-Set Docket et al. Mounting Plate for a Heating, No. Ventilation and Air Conditioning System” 070064] [Attorney Thorson, et “System and Method of Use for a User Docket al. Interface Dashboard of a Heating, No. Ventilation and Air Conditioning 070027] Network” [Attorney Grohman “Device Abstraction System and Method Docket for a Distributed-Architecture Heating, No. Ventilation and Air Conditioning 070016] Network” [Attorney Grohman, et “Communication Protocol System and Docket al. Method for a Distributed-Architecture No. Heating, Ventilation and Air 070079] Conditioning Network” [Attorney Hadzidedic “Memory Recovery Scheme and Data Docket Structure in a Heating, Ventilation and No. Air Conditioning Network” 080151] [Attorney Grohman “System Recovery in a Heating, Docket Ventilation and Air Conditioning No. Network” 080173] [Attorney Grohman, et “System and Method for Zoning a Docket al. Distributed-Architecture Heating, No. Ventilation and Air Conditioning 080131] Network” [Attorney Grohman, et “Programming and Configuration in a Docket al. Heating, Ventilation and Air No. Conditioning Network” 080160] [Attorney Mirza, et “General Control Techniques in a Docket al. Heating, Ventilation and Air No. Conditioning Network” 080146]

TECHNICAL FIELD

This application is directed, in general, to HVAC systems and, more specifically, to systems and methods for controlling HVAC system equipment.

BACKGROUND

Climate control systems, also referred to as HVAC systems (the two terms will be used herein interchangeably), are employed to regulate the temperature, humidity and air quality of premises, such as a residence, office, store, warehouse, vehicle, trailer, or commercial or entertainment venue. The most basic climate control systems either move air (typically by means of an air handler having a fan or blower), heat air (typically by means of a furnace) or cool air (typically by means of a compressor-driven refrigerant loop). A thermostat is typically included in a conventional climate control system to provide some level of automatic temperature and humidity control. In its simplest form, a thermostat turns the climate control system on or off as a function of a detected temperature. In a more complex form, the thermostat may take other factors, such as humidity or time, into consideration. Still, however, the operation of a thermostat remains turning the climate control system on or off in an attempt to maintain the temperature of the premises as close as possible to a desired set point temperature. Climate control systems as described above have been in wide use since the middle of the twentieth century and have, to date, generally provided adequate temperature management.

SUMMARY

One aspect provides an HVAC data processing and communication network. In an embodiment, the network includes a sensor and a local controller. The sensor is configured to detect a fault condition associated with operation of a demand unit. The local controller, associated with the demand unit, is configured to receive sensor data from the sensor and to communicate the sensor data over the network. A network controller is configured to receive the sensor data via the communication network and to generate an alert in the event that the sensor data indicates the fault condition.

Another aspect provides a method of manufacturing an HVAC data processing and communication network. In an embodiment, the method includes providing a sensor, a local controller and a network controller. The sensor is configured to detect a fault condition associated with operation of a demand unit. The local controller, associated with the demand unit, is configured to receive sensor data from the sensor and to communicate the sensor data over the network. The network controller is configured to receive the sensor data via the communication network and to generate an alert in the event that the sensor data indicates the fault condition.

Yet another aspect provides an HVAC data processing and communication network. In an embodiment, the network includes a heat pump. An indoor unit is configured to cooperate with the heat pump to operate in a cooling mode. An auxiliary heater is configured to temper cooled air output by the indoor unit during a defrost cycle of the heat pump. A controller is configured to detect operation of the auxiliary heater during the cooling mode, and to disable the auxiliary heater in the event that the operation is detected.

BRIEF DESCRIPTION

Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a high-level block diagram of an HVAC system according to various embodiments of the disclosure;

FIG. 2 is a high-level block diagram of one embodiment of an HVAC data processing and communication network;

FIG. 3 is a block diagram of a local controller of the disclosure;

FIG. 4 is a block diagram of a networked HVAC system device of the disclosure;

FIG. 5 illustrates an embodiment of an outdoor unit;

FIG. 6 illustrates an embodiment of an indoor unit; and

FIGS. 7 and 8 illustrate methods of the disclosure.

DETAILED DESCRIPTION

As stated above, conventional climate control systems have been in wide use since the middle of the twentieth century and have, to date, generally provided adequate temperature management.

However, it has been realized that more sophisticated control and data acquisition and processing techniques may be developed and employed to improve the installation, operation and maintenance of climate control systems.

Described herein are various embodiments of an improved climate control, or HVAC, system in which at least multiple components thereof communicate with one another via a data bus. The communication allows identity, capability, status and operational data to be shared among the components. In some embodiments, the communication also allows commands to be given. As a result, the climate control system may be more flexible in terms of the number of different premises in which it may be installed, may be easier for an installer to install and configure, may be easier for a user to operate, may provide superior temperature and/or relative humidity (RH) control, may be more energy efficient, may be easier to diagnose, may require fewer, simpler repairs and may have a longer service life.

FIG. 1 is a high-level block diagram of a networked HVAC system, generally designated 100. The HVAC system 100 may be referred to herein simply as “system 100” for brevity. In one embodiment, the system 100 is configured to provide ventilation and therefore includes one or more air handlers 110. In an alternative embodiment, the ventilation includes one or more dampers 115 to control air flow through air ducts (not shown.) Such control may be used in various embodiments in which the system 100 is a zoned system. In an alternative embodiment, the system 100 is configured to provide heating and therefore includes one or more furnaces 120, typically associated with the one or more air handlers 110. In an alternative embodiment, the system 100 is configured to provide cooling and therefore includes one or more refrigerant evaporator coils 130, typically associated with the one or more air handlers 110. Such embodiment of the system 100 also includes one or more compressors 140 and associated condenser coils 142, which are typically associated with one or more so-called “outdoor units” 144. The one or more compressors 140 and associated condenser coils 142 are typically connected to an associated evaporator coil 130 by a refrigerant line 146. In an alternative embodiment, the system 100 is configured to provide ventilation, heating and cooling, in which case the one or more air handlers 110, furnaces 120 and evaporator coils 130 are associated with one or more “indoor units” 148, e.g., basement or attic units that may also include an air handler.

For convenience in the following discussion, a demand unit 155 is representative of the various units exemplified by the air handler 110, furnace 120, and compressor 140, and more generally includes an HVAC component that provides a service in response to control by the control unit 150. The service may be, e.g., heating, cooling, humidification, dehumidification, or air circulation. A demand unit 155 may provide more than one service, and if so, one service may be a primary service, and another service may be an ancillary service. For example, for a heating unit that also circulates air, the primary service may be heating, and the ancillary service may be air circulation (e.g. by a blower).

The demand unit 155 may have a maximum service capacity associated therewith. For example, the furnace 120 may have a maximum heat output (often expressed in terms of British Thermal Units (BTU) or Joules), or a blower may have a maximum airflow capacity (often expressed in terms of cubic feet per minute (CFM) or cubic meters per minute (CMM)). In some cases, the demand unit 155 may be configured to provide a primary or ancillary service in staged portions. For example, blower may have two or more motor speeds, with a CFM value associated with each motor speed.

One or more control units 150 control one or more of the one or more air handlers 110, the one or more furnaces 120 and/or the one or more compressors 140 to regulate the temperature of the premises, at least approximately. In various embodiments to be described, the one or more displays 170 provide additional functions such as operational, diagnostic and status message display and an attractive, visual interface that allows an installer, user or repairman to perform actions with respect to the system 100 more intuitively. Herein, the term “operator” will be used to refer collectively to any of the installer, the user and the repairman unless clarity is served by greater specificity.

One or more separate comfort sensors 160 may be associated with the one or more control units 150 and may also optionally be associated with one or more displays 170. The one or more comfort sensors 160 provide environmental data, e.g. temperature and/or humidity, to the one or more control units 150. An individual comfort sensor 160 may be physically located within a same enclosure or housing as the control unit 150, in a manner analogous with a conventional HVAC thermostat. In such cases, the commonly housed comfort sensor 160 may be addressed independently. However, the one or more comfort sensors 160 may be located separately and physically remote from the one or more control units 150. Also, an individual control unit 150 may be physically located within a same enclosure or housing as a display 170, again analogously with a conventional HVAC thermostat. In such embodiments, the commonly housed control unit 150 and display 170 may each be addressed independently. However, one or more of the displays 170 may be located within the system 100 separately from and/or physically remote to the control units 150. The one or more displays 170 may include a screen such as a liquid crystal or OLED display (not shown).

Although not shown in FIG. 1, the HVAC system 100 may include one or more heat pumps in lieu of or in addition to the one or more furnaces 120, and one or more compressors 140. One or more humidifiers or dehumidifiers may be employed to increase or decrease humidity. One or more dampers may be used to modulate air flow through ducts (not shown). Air cleaners and lights may be used to reduce air pollution. Air quality sensors may be used to determine overall air quality.

Finally, a data bus 180, which in the illustrated embodiment is a serial bus, couples the one or more air handlers 110, the one or more furnaces 120, the one or more evaporator condenser coils 142 and compressors 140, the one or more control units 150, the one or more remote comfort sensors 160 and the one or more displays 170 such that data may be communicated therebetween or thereamong. As will be understood, the data bus 180 may be advantageously employed to convey one or more alarm messages or one or more diagnostic messages. All or some parts of the data bus 180 may be implemented as a wired or wireless network.

The data bus 180 in some embodiments is implemented using the Bosch CAN (Controller Area Network) specification, revision 2, and may be synonymously referred to herein as a residential serial bus (RSBus) 180. The data bus 180 provides communication between or among the aforementioned elements of the network 200. It should be understood that the use of the term “residential” is nonlimiting; the network 200 may be employed in any premises whatsoever, fixed or mobile. Other embodiments of the data bus 180 are also contemplated, including e.g., a wireless bus, as mentioned previously, and 2-, 3- or 4-wire networks, including IEEE-1394 (Firewire™, i.LINK™, Lynx™), Ethernet, Universal Serial Bus (e.g., USB 1.x, 2.x, 3.x), or similar standards. In wireless embodiments, the data bus 180 may be implemented, e.g., using Bluetooth™, Zibgee or a similar wireless standard.

FIG. 2 is a high-level block diagram of one embodiment of an HVAC data processing and communication network 200 that may be employed in the HVAC system 100 of FIG. 1. One or more air handler controllers (AHCs) 210 may be associated with the one or more air handlers 110 of FIG. 1. One or more integrated furnace controllers (IFCs) 220 may be associated with the one or more furnaces 120. One or more damper controller modules 215, also referred to herein as a zone controller module 215, may be associated with the one or more dampers 115. One or more unitary controllers 225 may be associated with one or more evaporator coils 130 and one or more condenser coils 142 and compressors 140 of FIG. 1. The network 200 includes an active subnet controller (aSC) 230 a and an inactive subnet controller (iSC) 230 i. The aSC 230 a may act as a network controller of the system 100. The aSC 230 a is responsible for configuring and monitoring the system 100 and for implementation of heating, cooling, humidification, dehumidification, air quality, ventilation or any other functional algorithms therein. Two or more aSCs 230 a may also be employed to divide the network 200 into subnetworks, or subnets, simplifying network configuration, communication and control. Each subnet typically contains one indoor unit, one outdoor unit, a number of different accessories including humidifier, dehumidifier, electronic air cleaner, filter, etc., and a number of comfort sensors, subnet controllers and user interfaces. The iSC 230 i is a subnet controller that does not actively control the network 200. In some embodiments, the iSC 230 i listens to all messages broadcast over the data bus 180, and updates its internal memory to match that of the aSC 230 a. In this manner, the iSC 230 i may backup parameters stored by the aSC 230 a, and may be used as an active subnet controller if the aSC 230 a malfunctions. Typically there is only one aSC 230 a in a subnet, but there may be multiple iSCs therein, or no iSC at all. Herein, where the distinction between an active or a passive SC is not germane the subnet controller is referred to generally as an SC 230.

A user interface (UI) 240 provides a means by which an operator may communicate with the remainder of the network 200. In an alternative embodiment, a user interface/gateway (UI/G) 250 provides a means by which a remote operator or remote equipment may communicate with the remainder of the network 200. Such a remote operator or equipment is referred to generally as a remote entity. A comfort sensor interface 260, referred to herein interchangeably as a comfort sensor (CS) 260, may provide an interface between the data bus 180 and each of the one or more comfort sensors 160. The comfort sensor 260 may provide the aSC 230 a with current information about environmental conditions inside of the conditioned space, such as temperature, humidity and air quality.

For ease of description, any of the networked components of the HVAC system 100, e.g., the air handler 110, the damper 115, the furnace 120, the outdoor unit 144, the control unit 150, the comfort sensor 160, the display 170, may be described in the following discussion as having a local controller 290. The local controller 290 may be configured to provide a physical interface to the data bus 180 and to provide various functionality related to network communication. The SC 230 may be regarded as a special case of the local controller 290, in which the SC 230 has additional functionality enabling it to control operation of the various networked components, to manage aspects of communication among the networked components, or to arbitrate conflicting requests for network services among these components. While the local controller 290 is illustrated as a stand-alone networked entity in FIG. 2, it is typically physically associated with one of the networked components illustrated in FIG. 1.

FIG. 3 illustrates a high-level block diagram of the local controller 290. The local controller 290 includes a physical layer interface (PLI) 310, a non-volatile memory (NVM) 320, a RAM 330, a communication module 340 and a functional block 350 that may be specific to the demand unit 155, e.g., with which the local controller 290 is associated. The PLI 310 provides an interface between a data network, e.g., the data bus 180, and the remaining components of the local controller 290. The communication module 340 is configured to broadcast and receive messages over the data network via the PLI 310. The functional block 350 may include one or more of various components, including without limitation a microprocessor, a state machine, volatile and nonvolatile memory, a power transistor, a monochrome or color display, a touch panel, a button, a keypad and a backup battery. The local controller 290 may be associated with a demand unit 155, and may provide control thereof via the functional block 350, e.g. The NVM 320 provides local persistent storage of certain data, such as various configuration parameters, as described further below. The RAM 330 may provide local storage of values that do not need to be retained when the local controller 290 is disconnected from power, such as results from calculations performed by control algorithms. Use of the RAM 330 advantageously reduces use of the NVM cells that may degrade with write cycles.

The disclosure recognizes that various innovative system management solutions are needed to implement a flexible, distributed-architecture HVAC system, such as the system 100. More specifically, cooperative operation of devices in the system 100, such as the air handler 110, outdoor unit 144, or UI 240 is improved by various embodiments presented herein. More specifically still, embodiments are presented of detecting a fault in an HVAC system and advantageously reporting the fault to a user, installer or manufacturer in a timely manner to protect the user, the HVAC system and an associated structure.

FIG. 4 illustrates a device 410 according to the disclosure. The following description pertains to the HVAC data processing and communication network 200 that is made up of a number of system devices 410 operating cooperatively to provide HVAC functions. Herein after the system device 410 is referred to more briefly as the device 410 without any loss of generality. The term “device” applies to any component of the system 100 that is configured to communicate with other components of the system 100 over a wired or wireless network. Thus, the device 410 may be, e.g., the air handler 110 in combination with its AHC 210, or the furnace 120 in combination with its IFC 220. This discussion may refer to a generic device 410 or to a device 410 with a specific recited function as appropriate. An appropriate signaling protocol may be used to govern communication of one device with another device. While the function of various devices 410 in the network 200 may differ, each device 410 shares a common architecture for interfacing with other devices, e.g. the local controller 290 appropriately configured for the HVAC component 420 with which the local controller 290 is associated. The microprocessor or state machine in the functional block 350 may operate to perform any task for which the device 410 is responsible, including, without limitation, sending and responding to messages via the data bus 180, controlling a motor or actuator, or performing calculations.

In various embodiments, signaling between devices 410 relies on messages. Messages are data strings that convey information from one device 410 to another device 410. The purpose of various substrings or bits in the messages may vary depending on the context of the message. Generally, specifics regarding message protocols are beyond the scope of the present description. However, aspects of messages and messaging are described when needed to provide context for the various embodiments described herein.

Turning now to FIG. 5, illustrated is an embodiment of the disclosure of an outdoor unit generally designated 500. The outdoor unit 500 is illustrated without limitation as a communicating heat pump unit. “Communicating” refers to the outdoor unit 500 being configured to communicate with other devices on the network 200 via the data bus 180. The term “outdoor” is used for notational convenience, but does not limit the location of the outdoor unit 500 to being located outside of a building or confined structure. Instead, the outdoor unit 500 is typically placed in a location from which it can dump waste heat while cooling a conditioned space, or a location from which it can extract heat while heating the conditioned space. The outdoor unit 500 includes a heat pump controller (HPC) 510 and coils 520. The HPC 510 accepts messages addressed thereto via the data bus 180 and controls a compressor 530 and a fan motor 540 in response thereto.

The HPC 510 may configure the compressor 530 and the fan motor 540 according to one or more messages received from another device on the data bus 180, e.g., the aSC 230 a. When operating, the compressor 530 causes refrigerant to flow via refrigerant lines 550 to and from an indoor unit, e.g. an air handler. Air caused to flow over the coils 520 by the fan motor 540 extracts heat from, or provides heat to, the refrigerant, depending on whether the outdoor unit is configured to heat or cool.

In some embodiments, discussed in greater detail below, the HPC 510 also includes a control line 560 configured to control the operation of an auxiliary heat source associated with the indoor unit. In some embodiments, the control line 560 is only present when the outdoor unit 500 is a non-communicating outdoor unit. The outdoor unit is non-communicating when the HPC 510 is not configured to communicate over the data bus 180. In such embodiments, the outdoor unit 500 may receive control signals from an indoor unit, e.g. air handler, via one or more control lines.

Turning to FIG. 6, illustrated is an embodiment of an indoor unit generally designated 600. The indoor unit is shown without limitation as comprising an air handler 605. In various embodiments, the indoor unit 600 is configured to cooperate with the outdoor unit 500 to operate therewith in a cooling mode. The cooling mode, e.g., provides chilled air to the structure with which the outdoor unit 500 and the indoor unit 600 are associated.

The indoor unit 600 is presented as a non-limiting example of a component of the system 100 that may be configured to detect and report various fault conditions. In one embodiment, the indoor unit 600 is configured to sense various fault conditions that have the potential to damage the HVAC system 100 and/or the structure in which the system 100 is installed. In the illustrated embodiment, the indoor unit 600 includes a blower 610. The blower 610 may move air over a heat exchanger 620 and a heater 630. The heat exchanger 620 may be configurable as a condensing heat exchanger or an evaporating heat exchanger depending on whether the aSC 230 a sends instructions for the outdoor unit 500 to operate in cooling mode or heating mode. In a heat pump system, the heat exchanger 620 may operate as both a condensing and an evaporating heat exchanger depending on whether the system 100 is configured to heat or cool the structure. The heater 630 may be, e.g., an auxiliary heater that may be used to temper air output by the indoor unit 600 when the system 100 is configured to defrost the coils 620. While illustrated as an auxiliary heater, in other embodiments the heater 630 is a furnace.

As understood by those skilled in the pertinent art, during a heating mode a heat pump system operates to circulate warm refrigerant through indoor heat exchanger coils, and to circulate cool refrigerant through the outdoor heat exchanger coils. During a cooling mode, warm refrigerant flows through the indoor coils and warm refrigerant flows through the outdoor coils. While in the heating mode, the outdoor coils may accumulate frost under some conditions. Thus, a defrost mode cycle is typically used periodically to remove possible accumulated frost on the outdoor coils. As used herein, a heat pump operates in a defrost mode when the heat pump interrupts a heating mode to circulate warm refrigerant through the outdoor coils to remove possible frost accumulation.

The indoor unit 600 may be instrumented with one or more sensors, illustrated as sensors 640 a-640 e, e.g. The sensor 640 a is located in a drip pan 650 located below the heat exchanger 620. The drip pan 650 may catch condensation from the heat exchanger 620. If the water level in the drip pan 650 rises above a predetermined level, this condition may indicate, e.g., a blockage in a drain line. If the system 100 is allowed to continue operating, overflowing water may cause damage to the air handler 110 or the floor therebelow, e.g. The sensor 640 b may detect an icing condition associated with the heat exchanger 620. An icing condition may be, e.g., an actual presence of ice, or a temperature associated with ice formation (e.g., a temperature below freezing). Excessive frost may cause the system 100 to operate in an inefficient operational regime, or may cause a pressure differential across the heat exchanger 620 that may cause damage thereto. The sensors 640 c, 640 d are located to detect operation of the heater 630. For example, a temperature gradient detected by the sensors 640 c, 640 d may indicate the auxiliary heater is operating.

The sensor 640 e is configured to sense the presence of a control signal on the control line 660. The output of the sensor 640 e may be used as another means to determine the operating state of the heater 630.

In a conventional HVAC system, a fault condition such as the described examples may cause the conventional system to shut down. However, no specific information is provided to the operator of the conventional system, resulting in potentially costly diagnostics to determine the source of the error.

HVAC systems of the disclosure, e.g., the system 100, may be configured to monitor one or more sensors such as the sensors 640 a-640 e. When one or more sensors indicate a fault condition in the system 100, the system 100 may be shut down by the aSC 230 a. In contrast with conventional HVAC systems, the aSC 230 a may cause the UI 240 to display one or more alarms, diagnostic messages or informational alerts to the operator. The UI 240 may thereby inform the operator of the nature and severity of the error, the extent to which the system 100 is disabled, and provide information that may be used to rapidly correct the fault condition.

In one embodiment, a local controller may interrogate the sensors that detect a fault condition. The local controller may then provide information regarding the status of the sensors to other devices on the HVAC network. In a nonlimiting example, the air handler 605 includes an air handler controller (AHC) 660. The AHC 660 may generally provide an interface between the data bus 180 and the various components associated with the air handler 605. Thus, the AHC 660 may accept messages from the SC 230, and may provide commands to the blower 610 or the heater 630 in response to the messages.

The AHC 660 is also configured to receive sensor data from the sensors 640 a-e. In FIG. 6 the explicit connection from the sensor 640 e is also representative of the connection from the sensors 640 a-d to the AHC 660. The AHC 660 may form messages containing information regarding the status of one or more of the sensors 640 a-e. In some embodiments, a message may simply be a status message that makes the status of a particular sensor available, e.g., to be displayed on the UI 240. In some embodiments, the message may be an alarm message. The SC 230 is configured to originate messages to and receive messages from the AHC 660 via the data bus 180. The SC 230 or the AHC 660 may then generate an alert message instructing the UI 240 to display an error message to be displayed to the operator. Alternatively or in combination to displaying the alert message, the SC 230 may also generate an alert message instructing the UI/G 250 to transmit an error message to a remote entity.

Depending on the severity of the fault condition, the active SC 230 may limit an operational aspect of the air handler 605, or may disable further operation of the air handler 605 or the entire system 100. In one embodiment, the sensor 640 a reports that a water level in a drip pan 650 has exceeded a predetermined level. The aSC 230 a may be configured to take immediate remedial action in such a case, e.g., shutting down the system 100, displaying an error alert on the UI 240, and alerting service personnel via the UI/G 250. In another embodiment, the aSC 230 a may disable cooling operation of a heat pump but retain heating operation, since a heat pump does not typically produce condensation on the indoor coil during heating operation. In another embodiment, the aSC 230 a initiates heat pump heating cycle, e.g., circulating warm refrigerant through the heat exchanger 620, in response to detecting ice on the heat exchanger 620 via the sensor 640 b. In another embodiment, the aSC 230 a may disable cooling operation of a heat pump while commanding the blower 610 to continue moving air over the heat exchanger 620 at a same or a different rate as a rate used during the cooling operation.

In some embodiments, one or more sensors in the air handler 605 is a mechanical switch, such as, e.g., a switch that detects a misaligned mechanical component such as open panel in the air handler 605 housing. The AHC 660 and/or the aSC 230 a may be configured to “debounce” the output of the mechanical switch in a manner analogous to switch debouncing provided by discrete electronics. Configuration may be, e.g., in the form of such discrete electronics, e.g., a debouncing flip-flop located within the AHC 660, or software coding within the aSC 230 a. Thus, spurious error reports may be advantageously avoided that might otherwise require the attention of the operator or a service provider.

In most cases, the heater 630 only operates to temper the air from the air handler 605 during a defrost cycle, as described above. Under some fault conditions, the heater 630 may operate at other times, or may operate continuously. For example, the control line 660 may be connected incorrectly when the system 100 is installed, or a logic failure in the HPC 610 may enable the heater 630 at the wrong time. Such operation may waste energy, or possibly create a fire hazard. The sensors 640 c, 640 d, 640 e provide a means to detect such fault conditions.

In one embodiment, the SC 230 determines that there is a temperature rise from the sensor 640 d to the sensor 640 c when the outdoor unit 500 and the indoor unit 600 are configured to provide cooling to the structure the units 500, 600 are associated with. In this context, the units 500, 600 are not configured to provide cooling when they are configured to defrost the coils 620 of the outdoor unit 500. The presence of the temperature rise while the units 500, 600 are configured for cooling may indicate that the heater 630 is operating. Generally, however, such operation during cooling indicates a fault condition.

In an alternate embodiment, the sensor 640 e may indicate a voltage on or current through the control line 660, the voltage or current being consistent with operation of the heater 630 during cooling. Detection of heater 630 operation via the sensor 640 e may be particularly advantageous when the outdoor unit 500 is a non-communicating heat pump. In such case, the HPC 610 may disable the heater 630 upon receiving an appropriate control signal from the indoor unit 600. The control signal may be generated, e.g., by the AHC 660 after receiving an appropriately configured message from the SC 230. In a manner similar to that described with respect to the sensors 640 c, 640 d, the AHC 660 may report the reading from the sensor 640 e to the SC 230. The subnet controller may then take action as described earlier.

Those skilled in the pertinent art are able to determine a configuration of sensors that would be used if the heater 630 is a furnace.

Moving now to FIG. 7, illustrated is a method generally designated 700 of manufacturing an HVAC data processing and communication network. The method 700 is presented without limitation using the system 100 by way of example. Those skilled in the pertinent art will appreciate that the method may be implemented using systems configured differently than the system 100.

The method 700 begins with a state 701, which may be reached from any desired calling routine of a control algorithm, e.g. In a step 710, local controller is provided that is associated with a demand unit. The local controller is configured to detect a fault condition associated with the operation of the demand unit. The fault condition may be, e.g., the presence of water or frosting conditions. Herein and in the claims, “provided” means that a device, item, structural element, etc., may be manufactured by an individual or business entity performing the disclosed methods, or may be obtained by that individual or entity from a source other than the individual or entity. The demand unit may be, e.g., any of the air handler 110, furnace 120, outdoor unit/unitary control, or the indoor unit 600. The demand unit is addressable via a communication network such as the data bus 170.

In a step 720, a local controller, e.g., the local controller 290, is provided that is associated with the demand unit. The local controller is configured to receive sensor data from the sensor and to communicate the sensor data over a data bus, e.g., the data bus 180.

In a step 730, a subnet controller, e.g., the aSC 230 a, is provided. The subnet controller is configured to receive the sensor data via the data bus. The subnet controller is further configured to generate an alert in the event that the sensor data indicates the fault condition of the demand unit. The method ends with a state 799, from which a control algorithm may return to a calling routine.

Optionally, the method 700 includes configuring the controller to instruct a user interface to display an error message when generating the alert. Optionally, the controller may be provided already configured as described. The controller may be configured to instruct a gateway to send an error message to a remote entity when generating the alert. The controller, which may be a local controller 290, may be configured to change an operational aspect of the system 100 in response to the fault condition. Changing the operational aspect may include disabling operation of one or more devices on the network 200 in response to the fault condition, up to and including disabling operation of the entire system 100.

Turning now to FIG. 8, illustrated is another method, generally designated 800, of manufacturing an HVAC data processing and communication network. The method 800 is presented without limitation using the system 100 by way of example. Those skilled in the pertinent art will appreciate that the method may be implemented using systems configured differently than the system 100.

The method 800 begins with a state 805, which may be reached from any desired calling routine of a control algorithm, e.g. In a step 810, a heat pump is provided that is configured to operate in a cooling mode and a defrost mode. The heat pump may be configured, e.g. as an outdoor unit such as the outdoor unit 500. The defrost mode may be a heat pump cycle, e.g., operating the heat pump to circulate warm refrigerant through the coil 620 for a duration sufficient to melt ice thereon. In a step 820, a communicating indoor unit is configured to cooperate with the heat pump to operate in the cooling mode. The indoor unit may be configured, e.g., as exemplified by the indoor unit 600. In a step 830 an auxiliary heater, e.g., the heater 630 or a furnace, is provided that is configured to temper cooled air output by the indoor unit while the heat pump is operating in the defrost mode. In a step 840, a controller is provided that is configured to disable the auxiliary heater in the event that the auxiliary heater operates during the cooling mode. The method 800 ends with a terminating step 850, from which a control algorithm may return to a calling routine.

Optionally, a sensor is configured to determine that the auxiliary heater is operating in the cooling mode. One or more sensors may be configured to determine that there is a temperature rise of air passing through the auxiliary heater. In another embodiment, a sensor is configured to detect a voltage or a current configured to enable operation of the auxiliary heater. The heat pump may be a non-communicating heat pump, wherein a heat pump controller is the controller configured to disable the auxiliary heater, e.g., the HPC 610. In some cases, the controller is a subnet controller, e.g., the SC 230. A subnet controller may be configured to cause an alert to be generated in response to the disabling of the auxiliary heater. The alert maybe a message displayed on a user interface screen, or may be communicated via a gateway to a remote entity. Optionally the auxiliary heater is a furnace. Also optionally, the heat pump, communicating indoor unit, auxiliary heater configured and controller may be integrated.

Those skilled in the art to which this application relates will appreciate that other and further additions, deletions, substitutions and modifications may be made to the described embodiments. 

1. An HVAC data processing and communication network, comprising: a sensor configured to detect a fault condition associated with operation of a demand unit; a local controller associated with said demand unit and configured to receive sensor data from said sensor and to communicate said sensor data over said network; and a network controller configured to receive said sensor data via said communication network and to generate an alert in the event that said sensor data indicates said fault condition.
 2. The HVAC data processing and communication network as recited in claim 1, further comprising a user interface, wherein said alert includes instructing said user interface to display an error message.
 3. The HVAC data processing and communication network as recited in claim 1, further comprising a gateway, wherein said alert includes instructing said gateway to send an error message to a remote entity.
 4. The HVAC data processing and communication network as recited in claim 1, wherein said controller is further configured to change an operational aspect of said network in response to said fault condition.
 5. The HVAC data processing and communication network as recited in claim 4, wherein said controller disables operation of said demand unit.
 6. The HVAC data processing and communication network as recited in claim 4, wherein said controller disables operation of the entire network.
 7. The HVAC data processing and communication network as recited in claim 4, wherein said demand unit is a heat pump, and controller is further configured to initiate a heating cycle when said sensor detects said icing condition.
 8. A method of manufacturing an HVAC data processing and communication network, comprising: provide a sensor configured to detect a fault condition associated with operation of a demand unit; provide a local controller associated with said demand unit and configured to receive sensor data from said sensor and to communicate said sensor data over a data bus; and provide a subnet controller configured to receive said sensor data via said data bus and to generate an alert in the event that said sensor data indicates said fault condition.
 9. The method as recited in claim 8, further comprising configuring said subnet controller to instruct a user interface to display an error message when generating said alert.
 10. The method as recited in claim 8, further comprising configuring said subnet controller to instruct a gateway to send an error message to a remote entity when generating said alert.
 11. The method as recited in claim 8, configuring said subnet controller to change an operational aspect of said network in response to said fault condition.
 12. The method as recited in claim 8, further comprising configuring said subnet controller to disable operation of said demand unit in response to said fault condition.
 13. The method as recited in claim 8, further comprising configuring said subnet controller to disable operation of the entire network in response to said fault condition.
 14. The method as recited in claim 8, wherein said demand unit is a heat pump, and subnet controller is further configured to initiate a heating cycle when said sensor detects said icing condition.
 15. An HVAC data processing and communication network; comprising: a heat pump; a communicating indoor unit configured to cooperate with said heat pump to operate in a cooling mode; an auxiliary heater configured to temper cooled air output by said indoor unit during a defrost cycle of said heat pump; and a controller configured to detect operation of said auxiliary heater during said cooling mode, and to disable said auxiliary heater in the event that said operation is detected.
 16. The HVAC data processing and communication network as recited in claim 15, further comprising a sensor configured to determine that said auxiliary heater operates during said cooling mode.
 17. The HVAC data processing and communication network as recited in claim 16, wherein said sensor detects a temperature rise of air passing through said auxiliary heater.
 18. The HVAC data processing and communication network as recited in claim 16, wherein said sensor detects a control voltage configured to enable operation of said auxiliary heater.
 19. The HVAC data processing and communication network as recited in claim 15, wherein said heat pump is a non-communicating heat pump and said controller is a heat pump controller.
 20. The HVAC data processing and communication network as recited in claim 15, further comprising a subnet controller configured to issue an alert in response to disabling said auxiliary heater. 